This is especially the case if you have a quality one, but it's sometimes the case for slightly cheaper boards, you've noticed that they don't have legs, they're really "boards", in the sense: a rectangular piece without really a top or bottom.
And as a result, when you put it on your work surface, you have an almost immediate soapy effect, it slides or moves as soon as you start cutting on it, which is quickly a pain in the ass.
How to avoid this ?
Very simple, do as the pros do: Fold a cloth in half and slide it under your board, don't let anything stick out. The cloth acts as a kind of shock absorber that prevents the board from slipping, it remains firmly in place throughout your cuts.
In short: To prevent your cutting board from moving during your cuts, slide a cloth folded in half underneath.